- To gently land a rocket ship on the surface of Mars,
one must overcome the most ornery physics.
When a spacecraft returns to Earth,
the relatively thick atmosphere helps
to slow down that speeding bullet.
But on Mars, the aerodynamics are not so friendly.
The atmosphere is much thinner,
with the densest Martian air
only about as thick as what you'll find on Earth
at 100,000 feet above sea level,
more than three times the altitude
of the peak of Mount Everest.
According to NASA, "Of over 40 missions sent to Mars,
fewer than half have been successful"
and they want to send people there.
Jim Reuter, NASA associate administrator
for the Space Technology Mission Directorate,
calls it, "The Anti-Goldilocks atmosphere.
It's thick enough that it causes you problems
and not thin enough to help you."
But space scientists think they figured out a way
to pull more drag out of literal thin air.
Engineers have developed new hardware,
an inflatable heat shield that might be the key.
It's called a Hypersonic Inflatable
Aerodynamic Decelerator or HIAD.
The technology could help NASA land astronauts
and massive cargo loads on the red planet in the late 2030s.
Now, a team at the space agency's Langley Research Center
in Virginia is ready to test its mettle in space.
Earlier this month, scientists and engineers gathered
to see the heat shield inflated
for the final time on Earth
before it shoots into orbit
on a United Launch Alliance Atlas V rocket in November.
The mission, known as the Bernard Kutter
Low-Earth Orbit Flight Test of an Inflatable Decelerator,
or LOFTID for short,
will take the experiment up
with a weather satellite on a trip around Earth
that passes over the North and South Poles.
The heat shield will stay put until
after the satellite's delivery,
then will inflate
as the spacecraft returns to Earth.
At a small demo in mid-June,
the gun metal gray shrouded heat shield,
looking like a giant mushroom cap,
ballooned out in a cavernous laboratory.
The contraption was 20 feet wide,
about the size of a small carousel,
with a catwalk stretched over top
for scientists and engineers to cross it.
Since NASA began in 1958,
the agency has relied on rocket engines
and rigid aeroshell heat shields to land spacecraft.
The aeroshell is a protective cover,
shielding the lander from the scorching heat of reentry.
From the first crewless Viking mission in the 1970s,
to NASA's most recent Curiosity Rover launched in 2011,
engineers have used the same heat shield technology
to get to Mars. But the classic technology is limiting.
A hard aeroshell can only be as big
as the diameter of a rocket's nose cone,
which holds the lander.
The larger the aeroshell, though,
the heavier the loads can be.
For sending astronauts to Mars,
scientists say they'll need to land about 20 to 45 tons.
So far, they've only landed less
than two tons on the Martian ground.
"Reliance on the old method has
also constrained spacecraft landings
to Mars Northern lowlands,
below the base elevation level
on the red planet," said Joe Del Corso
the project manager at Langley.
That's how an inflatable heat shield could come in handy.
The system is composed of a stack
of inner-tube-like rings strapped together.
It's synthetic material is 15 times stronger
than steel and able to withstand temperatures
over 2,900 degrees Fahrenheit.
The idea is to deploy it higher up in Mars' atmosphere,
expanding NASA's touchdown options
throughout the Martian Southern Highlands.
According to experts, it's a more realistic solution
than bundles of parachutes the size of a football field
or tens of extra tons of rocket fuel.
According to Del Corso,
"With classic technology,
you can land about 1.5 metric tons.
That's the equivalent of a well-instrumented golf cart.
With 20 to 40 metric tons,
we're talking about a ranch house,
fully furnished with a car in the carport.
That's what you have to have."
The $93 million mission to test the heat shield
in space is a partnership with the United Launch Alliance,
which will provide the ride
and the recovery of the NASA equipment after the launch.
The rocket will take off
from Vandenberg Space Force Base in California.
If all goes according to plan,
the heat shield will slow down the lofted vehicle
from over 25 times the speed of sound,
to under 610 miles per hour.
The inflated system will then separate
and splash down into the Pacific Ocean
with a parachute near Hawaii.
During the dissent,
it will eject a data recorder storing information
about the flight that a boat will retrieve from the water.
There's something in the mission
for the United Launch Alliance too.
Barb Egan, the company's Civil Space Program director says,
"The new heat shield could help
them recover spent boosters for reuse,"
referring to a notoriously expensive aspect of space travel.
The business hopes to one day use it
for its Vulcan heavy-lift rocket,
whose thrusters make up about 60% of each launch cost.
Egan says, "This is a giant leap in aeroshell technology,
to be able to bring our engines back quickly, easily, safely
and reuse that technology rather than throw it away."